Thirty-three patients less than 40 years of age were diagnosed at CS Dept. of Catholic University Medical College between 1979 and 1988 as having primary lung cancer. There were 22 men and 11 women; the average age was 36.3 years. The youngest patients was 23 years old. Eighteen male patients were only habitual smokers more than 1 pack per day. In the 33 cases, the distribution by tumor type was as follows: squamous cell carcinoma 36.4%[13 cases]; adenocarcinoma 33.3%[11 cases]; small cell carcinoma 24.2%[8 cases]; and large cell carcinoma 3.0%[1 case]. At the time of diagnosis, 2 patients[6.1%] had stage I disease, 2[6.1%] had stage II disease, 5[15.6%] had stage IIIA disease, 10[30.3%] had stage lllB disease, and 14[42.4%] had stage IV disease. Thirteen patients[36.4%] underwent an exploratory thoracotomy. Of these patients, 9[27.3%] had surgical resection[six lobectomies, two pneumonectomies, and one wedge resection]. Thirty-one patients were treated with palliative radiation therapy, chemotherapy, or combinations of each. The survival rate at 1 year, 3 year, and 5 year were 48.2%, 14.5%, and 8.3% respectively. But in the resectable 9 patients, they were 78.1%, 43.6%, and 33.3% respectively.